V2X communications involve communications to a vehicle from another device, or from a vehicle to another device. That other device may be another vehicle (vehicle-to-vehicle (V2V)), roadside infrastructure (vehicle-to-infrastructure (V2I)), a pedestrian (vehicle-to-pedestrian (V2P)), or any other device (vehicle-to-device (V2D)). The communication is typically a localized short-range communication, such as using the WLAN IEEE 802.11 family of standards (e.g. Wireless Access in Vehicular Environments (WAVE) communications), although the present application is not limited to such communications and may be implemented in coding position data in the context of V2X communications over a non-short-range channel.
One of the issues regularly encountered in intelligent transportation systems is the determination of position of another element in the system. For example, automated tolling systems typically need to identify the location of a passing vehicle for toll purposes (some systems refer to this as “lane assignment”). Information sent to the vehicle regarding approaching emergency vehicles, upcoming traffic problems or roadworks, or nearby roadside features or the like, may include location information for the nearby device or vehicle. Likewise, the vehicle may need to communicate its location to nearby vehicles or nearby roadside infrastructure.
Location information is typically obtained using a Global Navigation Satellite System (GNSS) such as the Global Positioning System (GPS) or the like. Location may be expressed in some cases using latitude and longitude coordinates expressed in decimal degrees, for example.
Location information in V2X typically needs to be communicated quickly and accurately, and may in some cases involve use of a congested channel with transmission collisions and/or low-energy transmissions.
Similar reference numerals may have been used in different figures to denote similar components.